Welsh Regional Water Resources Planning and Development Strategy
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|\\RA V 'oh.s \ ? z AAC NRA Awdurdod Afonydd Cenedloethol National Rivers Authority Rhanbarth Cymru Welsh Region Welsh Regional Water Resources Planning and Development Strategy Final Project Report July 1994 B I N N I E PARTNERS CONSULTING ENGINEERS A sia n ta eth y r A m g y lc h ed d C y m r u E n v ir o n m e n t A g e n c y W a l e s GWASANAETH LLYFRGELL A GWYBODAETH CENEDLAETHOL NATIONAL LIBRARY & INFORMATION SERVICE PRIF SWYDDFA/MAIN OFFICE Plas-yr-Afon/Rivers House Parc Busnes Llaneirwg/ St Mellons Business Park Heol Fortran/Fortran Road Llaneirwg/St Mellons Caerdydd/Cardiff CF3 OLT NR.A ^ a l e s ENVIRONMENT Ac cNCY 106254 EXECUTIVE SUMMARY The National Rivers Authority (NRA) has a statutory duty under the Water Resources Act 1991 to conserve, redistribute or otherwise augment water resources and secure the proper use of water resources. This duty does not relieve any water undertaker of the obligation to develop water resources for the purpose of performing any duty imposed on it by virtue of the Water Industry Act 1991. The NRA must have regard to the reasonable needs of all abstractors, particularly those of the water companies. Additionally, the NRA is charged as the guardian of the water environment. This report provides a policy framework for a Regional Water Resources Strategy for the sustainable development and ongoing management of water resources in the Welsh Region until 2021. It highlights the major issues and makes recommendations concerning the basis for decisions within the Region. Specific consideration has been given to: * the existing balance of resources and demands; * future demands for public water supply (PWS), industry, and agriculture; * the need to improve ‘low flow rivers’ resulting from overabstraction; * the selection of water resource options needed to meet justified needs. By virtue of the Region’s relatively abundant water resources several rivers in the Region are already major resource providers to other Regions and this could potentially increase. The proposed strategy has therefore been developed in parallel with the NRA’s National Water Resources Strategy, and strategic national resource development proposals affecting the Region arc addressed. The Region's water resources are reviewed in Section 2. The Welsh Region, the third largest of the eight NRA Regions, receives higher rainfall than any of the English Regions and includes a large number of major regulated rivers which represent the principal surface water resource of the Region. Groundwater is also important in the Region, being a source of water for many small private abstractions. However, much of the-Region is underlain by impermeable strata and groundwater provides only a limited resource for public water supply resources. The licence exemption status of a large part of Western Wales with respect to groundwater abstractions has resulted in a lack of detailed information on these resources and demands. The Welsh Region is a major net exporter of water. Imports to and exports from the Region are described. Section 3 identifies and quantifies current and historic demands for water, both human and environmental. Hydroelectric power generation is the largest user of water in the Region, although this is a non-consumptive use. Public water supply is the second largest user of water, with about 40% exported out of the Region. Other abstraction demands include industrial, agriculture and amenity and conservation. In addition to abstraction the Region’s rivers are important for several in-river demands. Navigation, angling and effluent dilution all make requirements on rivers. Equally importantly surface water and groundwater resources are required to meet the demands of the environment in the form of water for the soil, wetlands, rivers and estuaries. WRWRS.REP/75F/27 June 1994 This leads on to the forecasting of future demands in Section 4. Future demands for public water supply are forecast under a range of scenarios incorporating assumptions about growth in domestic and commercial consumption, per capita consumption, metering and leakage reduction. A consistent, multiple-component methodology, based on one developed in the NRA’s national resources development strategy project, has been employed. This leads to a demand forecast envelope which delimits growth in public water supply demand, ranging from 2% decrease to a 22% increase in demand in the Region. Future demands for private abstraction are also forecast, based on historic trends and consultation with representatives of industry and agriculture. Only spray irrigation and hydroelectric power generation are forecast to increase significantly over the planning horizon. The forecasts illustrate how sensitive the timing of new resource developments is to the assumptions made in the demand scenarios. Marginal demand for public water supply ranges from about 20 Ml/d to 100 Ml/d in 2021. Under the medium growth scenario demand is forecast to increase by about 6% producing a marginal demand of 28 Ml/d with deficits commencing in 1996. In Section 5 options for meeting the forecast marginal demands are explored. This includes saving water (demand management), re-allocation of water (reduction in licensed entitlement and incentive charging), and making more water available (resource development). Most of the marginal demands could be met through demand management measures and local source development. Under the high growth scenario one new resource development is identified as being required. Section 6 details the proposed water resources development strategy in the form of proposed water resources management policies and extensions to the public water supply network. Recommendations for further work by the NRA are also included. WRWRS.REP/75F/27 June 1994 CONTENTS Page GLOSSARY OF TERMS vi 1 INTRODUCTION 1 1.1 Background 1 1.2 Specific objectives of the project 1 2 REVIEW OF THE WATER RESOURCES OF THE REGION 3 2.1 Regional characteristics 3 2.2 Surface water resources 3 2.2.1 Section 20 Operating Agreements 5 2.3 Groundwater resources 7 2.4 Licensed abstraction in the Region 8 2.4.1 Licence-exempt areas in the Region 9 2.4.2 Surface water abstraction licensing policy 10 2.5 Public water supply resources 10 2.5.1 Source yields 11 2.5.2 Dwr Cymru resources 11 2.5.3 Wrexham & East Denbighshire Water Company resources 15 2.5.4 Chester Waterworks Company resources 16 2.5.5 Efficiency of use and constraints on yield 16 2.6 Private demands resources 17 2.7 Imports and exports of water 17 3 CURRENT AND HISTORIC DEMANDS FOR WATER 19 3.1 Introduction 19 3.2 General 19 3.3 Public water supply 21 3.3.1 Analysis of licensed quantity/yield/demand balance in 1992 21 3.4 Private demands 23 3.4.1 Private water supply 23 3.4.2 Power generation 23 3.4.3 Industrial 25 3.4.4 Agriculture 25 3.4.5 Fish farming 26 3.4.6 Amenity/Conservation 27 3.4.7 Other uses 27 3.5 In-river demands 27 3.5.1 Navigation 27 3.5.2 Angling and recreation 28 3.5.3 Aquatic ecology 28 3.5.4 Effluent dilution 29 3.6 Environmental needs for water 29 3.6.1 Water for the soil 29 3.6.2 Water for wetlands 29 3.6.3 Water for rivers 31 3.6.4 Water for estuaries 32 3.7 Regional water balance 32 4 FUTURE DEMANDS FOR WATER SUPPLY 34 4.1 Introduction 34 4.2 General 34 WRWRS.REP/75F/27 June 1994 i CONTENTS Page 4 FUTURE DEMANDS FOR WATER SUPPLY(CONT,D) 4.3 Regional Public Water Supply demands 34 4.3.1 Methodology for PWS demand scenarios 34 4.3.2 Assumptions underlying demand scenarios 36 4.3.3 Demand forecasts 39 4.3.4 Projected resources shortfall for PWS 40 4.4 Future demands for industry & agriculture 50 4.4.1 Power generation 50 4.4.2 Industry 52 4.4.3 Agriculture 52 4.4.4 Amenity/Conservation 53 4.5 Projected resources shortfall for private demands 53 4.6 Environmental deficits 59 4.6.1 Alleviation of low flows (ALF) 59 4.7 National water resource demands 61 4.7.1 Enlargement of Craig Goch 62 4.7.2 Other options 63 4.8 Afforestation 63 5 OPTIONS FOR A STRATEGY FOR WATER RESOURCES 65 5.1 Introduction 65 5.2 The options for saving water - demand management 66 5.2.1 Leakage reduction 66 5.2.2 Metering of domestic water use 67 5.2.3 Consumer education 68 5.2.4 Better design of water appliances 68 5.2.5 Industry 68 5.2.6 The National Abstraction Charging Scheme 68 5.3 The options for re-allocating water 69 5.3.1 Under-used licences and ‘inefficiently’ used licences 69 5.3.2 Incentive charging 69 5.4 Options for making more water available 69 5.4.1 Local source developments and extensions 70 5.4.2 Regulated rivers - use of spare unlicensed yield 70 5.4.3 Regulated rivers - Increases in yield 71 5.4.4 Inter-basin transfers 72 5.4.5 Conjunctive use schemes 73 5.4.6 Recommissioning of Schwyll source 73 5.5 Groundwater development 87 5.5.1 Use of minewaters as a resource 88 5.6 Use of effluent returns 88 5.7 Alternative water sources 89 5.8 Impact of barrage developments 89 5.9 Possible impacts of climate change on water resources 90 6 PROPOSED REGIONAL WATER RESOURCES STRATEGY 92 6.1 Introduction 92 6.2 Proposed policies for water resources management 92 6.2.1 Licensing of abstractions 92 6.2.2 Demand management 93 6.2.3 The reallocation of water 93 ii WRWRS.REP/75F/27 June 1994 CONTENTS 6 PROPOSED REGIONAL WATER RESOURCES STRATEGY (CONT’D) 6.3 Proposed extensions to public water supply network 93 6.3.1 Medium growth scenario 94 6.3.2 High growth scenario 94 6.4 Private abstractions 95 6.4.1 Spray irrigation 96 6.5 Recommended areas of further work 97 REFERENCES 98 BIBLIOGRAPHY 101 APPENDICES A Terms of Reference A1 B The geology of the